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Isolation and Transportation of the Highly Infectious Patient

Isolation and Transportation of the Highly Infectious Patient. Craig D. Thorne MD, MPH, FACP, FACOEM Assistant Professor, Occupational & Environmental Medicine Medical Director, Employee Health & Safety University of Maryland Medical Center Brian Schwartz, MD, CCFP(EM), FCFP

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Isolation and Transportation of the Highly Infectious Patient

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  1. Isolation and Transportation of the Highly Infectious Patient Craig D. Thorne MD, MPH, FACP, FACOEM Assistant Professor, Occupational & Environmental Medicine Medical Director, Employee Health & Safety University of Maryland Medical Center Brian Schwartz, MD, CCFP(EM), FCFP Assistant Professor, Faculty of Medicine, University of Toronto Sunnybrook Health Sciences Centre Vice-Chair, Ontario SARS Scientific Advisory Committee Scientific Advisor, Emergency Management Unit, Ontario MOHLTC

  2. What if the chicken crosses the road???

  3. Agenda • Describe highly infectious diseases in the 21st century • Apply a ‘hierarchy of controls’: isolation, infection control precautions, & personal protective equipment • Understand proven strategies for community & workplace containment • Apply essentials of safe pre- & inter-hospital transportation

  4. Outlining the risk: highly infectious diseases in the 21st century

  5. Working Group on Civilian Biodefense 1998 John Hopkins Center task force including: CDC FDA USAAMRID State/Local Health Dept Clinicians Researchers

  6. SARS…

  7. SARS epidemiology – worldwide • Nov. 2002 - July 2003: • 8427 probable cases • 29 counties (throughout Asia, Canada & U.S.) • 29 U.S. cases (no deaths) • Primarily a nosocomial epidemic! • In Canada, 77% of SARS cases resulted from in-hospital exposure; In Taiwan: 94% • HCWS: • Overall, 1707 HCWs = 21% (combined community & hospital transmission) • Secondary (person-to-person) transmission in hospitals: • Hong Kong: 62% HCWs • Vietnam: 57% HCWs • Canada: 51% HCWs WHO Update - JAMA 2003; 289

  8. SARS epidemiology – worldwide (cont) • 813 deaths overall • Overall mortality rate: 3-12%. Up to 45% if over age 60 • Public health experts are braced for possible resurgence WHO Update - JAMA 2003; 289

  9. SARS epidemiology – worldwide (cont)

  10. Why was SARS so challenging? • Nonspecific presentation: fever & respiratory symptoms (dyspnea & cough); looks like ‘flu’ • No rapid diagnostic test: presumptive diagnosis made based on symptoms & exposure history (travel or known contact); eventual confirmation by lab detection of specific viral components • Definitive mechanism of transmission remains unclear: contagious by large droplets (coughing, sneezing & talking). Fomite transmission? Does SARS virus remain suspended in air (i.e., airborne transmission)? • No specific medication or vaccine to prevent or treat SARS

  11. Plague…

  12. Plague: Historical Data • Three major world pandemics resulting in over 200 million deaths ( 6th, 14th, & 19th centuries) • Category A agent with high potential as a bio-weapon, widely available in many countries, easily aerosolized, highly contagious, high fatality rate. • Potential for bio-engineering of more virulent strains. • Potential for mass panic, civil unrest, & economic devastation.

  13. Plague: Clinical Issues • Gram negative bacillus, Yersenia pestis. • Transmitted via three routes: • Aerosol- infection dose is 100 to 500 organisms • Contact with infected secretions, fomites • Bites of rodent fleas- mice, rats, squirrels, chipmunks, dogs, cats, camels, rabbits, prairie dogs. • Incubation period is 2-4 days • Clinical syndromes: Pneumonic, bubonic & septicemic • Malaise, myalgias, HA, fever, rigors. • Sepsis & pneumonia presentation with hemoptysis & leucocytosis • 100% mortality within 2-3 days without prompt antimicrobial treatment. • Isolation technique is AIRBORNE, DROPLET & CONTACT ISOLATION.

  14. Smallpox…

  15. Smallpox • A disease which has existed in epidemic form worldwide for at least 3000 years. • Discovered by Jenner in 1796 which led to the vaccinia vaccination program & the establishment of the principals of vaccination. • Global eradication in 1977 in Somalia the last known naturally occurring case. • Vaccination worldwide ceased in 1980. • No known animal or environmental reservoirs. • A serious threat to civilian populations who are currently highly susceptible. • Two current smallpox caches worldwide; Atlanta, Georgia & Russia.

  16. Smallpox: Clinical Issues • Orthopoxvirus DNA virus – same group as vaccinia, cowpox & monkeypox. • Person to person spread thru droplet nuclei, aerosols or direct contact. • Infection dose is only a few virions thru the oropharyngeal or other mucus membrane • Secondary attack rate of 58% & mortality rate of >30% • Incubation period of 12 – 14 days. • Presentation with fever, toxemia & a characteristic rash: Centrifugal, initially papular, then vesicular, then pustular with pitted permanent scarring upon healing. • No specific treatment. • Prevention by vaccination of live virus vaccine; vaccinia virus which effectively interrupts transmission. • Isolation technique is AIRBORNE & CONTACT.

  17. Viral hemorrhagic fever…

  18. VHF • Zoonotic viruses primarily except for filoviruses whose reservoir remains unknown • Well suited for aerolization of small particles 1-5 um in size but more difficult than anthrax to grow & maintain viability.

  19. Avian influenza…

  20. Typical Influenza: Clinical Issues • Transmission by small particle aerosol of about 10 micrometers. • Incubation period of 1-2 days. • Attack rate of 10 - 40% over a 5-6 week period annually. • HA, fever, myalgia, severe prostration, pneumonia. • Diagnosis by culture or antigen detection in respiratory secretions. • Treatment with antiviral agents: amantadine, rimantadine, zanamivir, oseltamavir • Prevention by annual vaccination of inactivated or live attenuated vaccine produced yearly. Peak antibodies in 2-4 months. • Isolation technique is Droplet Precautions

  21. What Is Avian Flu? • Avian flu is an infection caused by bird flu virusesa • Occurs naturally among wild birds that carry the viruses but they usually do not get sick from them • Avian flu is very contagious among birds & can make domesticated birds very sick & kill them • Infected birds shed flu viruses in their saliva, nasal secretions & feces • Domesticated birds may become infected through contact witha: • Infected waterfowl or other infected poultry • Contact with contaminated surfaces (such as dirt or cages) or materials (such as water or feed) • Some migratory birds are carrying highly pathogenic H5N1 virusb • Sometimes long distances • Introducing virus to poultry along their migratory routes • Asian & European poultry affected a. Centers for Disease Control and Prevention. Key facts about avian influenza (bird flu) and avian influenza A (H5N1) virus. Available at: http://www.cdc.gov/flu/avian/geninfo/facts.htm. Accessed October 23, 2006. b. World Health Organization. Avian influenza ("bird flu") – Fact sheet. Available at: www.who.int/mediacentre/factsheets/avian_influenza/en/#role. Accessed October 23, 2006.

  22. Current H5N1 Avian Flu Strain is of Concern to Health Experts • Highly pathogenic avian virus – represents a significant threat to human healtha: • Especially virulent • Spread by migratory birds • Transmitted from birds to mammals • Some, though limited, human-to-human transmission • Little to no human immunity present in populationb • High human mortality ratec • Roughly 54% mortality rate • 100x greater than seasonal flu • 22x greater than 1918 pandemic a. US Dept of Health and Human Services. AvianFlu.gov. General Information. 2006. Available at: http://pandemicflu.gov/general/#what. Accessed October 23, 2006. b. Centers for Disease Control and Prevention. Avian influenza: current situation. Available at: http://www.cdc.gov/flu/avian/outbreaks/current.htm. Accessed October 20, 2006. c. Stimola AN. American Council on Science and Health. Avian influenza, or "bird flu": What you need to know [e-published]. Available at: http://www.acsh.org/printVersion/print_pub.asp?pubID=1294. Accessed October 20, 2006.

  23. H5N1 Human Infection Uncommon But Has Occurred • Confirmed cases of human infection from several subtypes of avian flu infection have been reporteda • Most have resulted from contact with infected poultry or surfaces contaminated with their infected secretions/excretions • It seems difficult for humans to acquire the H5N1 virus from birds & even more difficult for the virus to spread among peopleb • In fact, no suspected cases of person-to-person transmission of H5N1 have been confirmed, indicating that the species barrier is still fairly strongb • Health experts are concerned that further mutations of H5N1 could change the virus into a form easily transmitted from person to person – resulting in a worldwide outbreak of the disease or “pandemic.”b a. Centers for Disease Control and Prevention. Key facts about avian influenza (bird flu) and avian influenza A (H5N1) virus. Available at: http://www.cdc.gov/flu/avian/geninfo/facts.htm. Accessed October 23, 2006. b. Stimola AN. American Council on Science and Health. Avian influenza, or "bird flu": What you need to know [e-published]. Available at: http://www.acsh.org/printVersion/print_pub.asp?pubID=1294.Accessed October 20, 2006.

  24. Human Exposure to H5N1 • Recently, most patients infected with H5N1 have had a history of direct contact with diseased poultry • Playing • Preparing, butchering, eating • Plucking • Human-to-human transmission has been suggested in several household clusters • Intimate contact without precautions • Non-intimate social contact not implicated • Other environmental modes of transmission theoretically possible • Contaminated water • Contaminated hands • Untreated poultry feces as fertilizer World Health Organization. Avian influenza A (H5N1) infection in humans. N Engl J Med. 2005;353:1374-1385.

  25. Clinical Course of H5N1 Influenza in Humans • Clinical Course • Fever often first symptoma • Severe primary viral pneumoniab • Lymphopeniab • Impaired liver functionb • Renal impairmentb • Death • Death occurs an average of 9 or 10 days after the onset of illness (range, 6 to 30)c • More than half of the laboratory-confirmed cases have been fatald a. Chotpitayasunondh T, Ungchusak K, Hanshaoworakul W, et al. Human disease from influenza A (H5N1), Thailand, 2004. Emerg Infect Dis. 2005;11:201-209. b. Chan PK. Outbreak of avian influenza A (H5N1) virus infection in Hong Kong in 1997. Clin Infect Dis. 2002;34(Suppl 2):S58-S64. c. World Health Organization. Avian influenza A (H5N1) infection in humans. N Engl J Med. 2005;353:1374-1385. d. World Health Organization. Avian influenza ("bird flu") – Fact sheet. Available at: www.who.int/mediacentre/factsheets/avian_influenza/en/#role. Accessed October 23, 2006.

  26. H5N1 outbreaks continue to escalate • Outbreaks continuea • Turks & Iraqi Kurds die as poultry outbreaks spread • Africa, backyard poultry • Italy, Germany, Greece, Slovenia, Bulgaria, Azerbaijan, Iran & Austria, found in wild birds, mostly swans • Azerbaijan, investigations revealed contact with infected wild dead birds (swans) as the most plausible source of infection in several cases in childrenb • Indonesia, WHO reported unconfirmed evidence of human-to-human spreadb • 8 people in one family infected • First member likely through contact with infected poultry • This person then may have infected six others in the family • One of those six may have infected another family member • No further spread outside of the exposed family was documented or suspected a. New Scientist Web site. Timeline: bird flu. Available at: http://www.newscientist.com/article.ns?id=dn9977&print=true. Accessed October 23, 2006. b. Centers for Disease Control and Prevention. Avian influenza: current situation. Available at: http://www.cdc.gov/flu/avian/outbreaks/current.htm. Accessed October 20, 2006.

  27. Human Cases Since 2003 World Health Organization. Human cases since 2003. WHO/Map Production: Public Health Mapping and GIS Communicable Diseases (CDS) World Health Organization 2006. Available at: http://gamapserver.who.int/mapLibrary/Files/Maps/Global_H5N1inHumanCUMULATIVE_20060823.png. Accessed October 9, 2006.

  28. H5N1 – What’s happening now?

  29. Hierarchy of Controls

  30. Classic hierarchy of controls 1. Engineering & Environmental Controls 2. Administrative Controls & Work Practices* 3. Personal Protective Equipment * During an infectious disease outbreak, early identification of cases (an administrative control) is critical prior to the effective implementation of engineering controls such as isolation

  31. Level 1: Engineering & Environmental Controls • CDC: ‘the separation of ill persons with contagious disease’, using physical barriers & ventilation • Most reliable (do not rely on worker cooperation) • Most cost effective • E.g.: permanent facilities/systems such as: negative pressure isolation, general ventilation, local ventilation, filtration, & anterooms

  32. Level 2: Administrative Controls & Work Practices • Standard procedures to reduce duration, frequency & severity of exposures to HCWs, other patients & visitors • E.g.: safe transport & transport of the highly infectious patient • Includes education, drills, updates & re-training

  33. Level 3: Personal Protective Equipment (PPE) • Gloves, gowns, goggles/eye shields, masks & respirators • Important, but: • Requires proper: • Selection (considering route of transmission, size of infectious particle, infectious dose, etc.) • Use • Maintenance & disinfection • Does not reduce risk 100% even when properly used. Overall: • N-95 mask: 85% efficacy* • Hooded powered air purifying respirator (PAPR): 99.9% • PPE supplements higher control measures * based on: 1) NIOSH definition that an N-95 can filter out 95% of a 0.3 micron challenge, hence a maximum exposure of 5%, & 2) NIOSH assigned protection factor (APF) for a half-face respirator of 10 which allows the user to wear the respirator in a maximum of 10 times the permissible exposure limit ( PEL), hence a maximum exposure of 10 %

  34. “The SARS outbreak illustrated the critical importance of basic infection control precautions in health-care facilities”“Nosocomial transmission of SARS was often associated with noncompliance with the basic level if infectious control precautions (standard precautions), including hand hygiene” - World Health Organization

  35. Summary of controls used by Toronto hospitals

  36. Updated Hierarchy of Controls: Applying Lessons from SARS to Any Future Severe Respiratory Illness (SRI) Thorne, Khozin, McDiarmid – JOEM, July 2004

  37. Level 1: Engineering & Environmental Controls

  38. 1. Negative pressure isolation • Creating a pressure differential to prevent contaminated air from leaking out of a room into other areas of a facility

  39. 2. General ventilation • 2-step process: • Dilute contaminated air using clean air, then • Remove diluted air • Must be designed & maintained by experienced engineer • Expert agencies have established ventilation standards or guidelines for TB control. Also useful for SARS planning

  40. 3. Local ventilation • Controlling contaminant immediately at, or near, source • Especially important for high risk patient procedures (e.g., intubation, non-invasive ventilation, & bronchoscopy) • Possibilities when performing procedures: • Completely vented enclosure • Externally vented hood

  41. 4. Filtration • High-efficiency particulate aerosol (HEPA) filtration removes 99.97% of particles >/= 0.3 um diameter • CDC: Proven highly effective to prevent spread of Aspergillus & TB • Should be used even if air is blown to the outdoors so as to minimize risk of contaminated re-circulated air

  42. 5. Anterooms • Small rooms separating isolation rooms from hospital corridors to prevent the escape of infectious particles • Features: • negative pressure (or neutral) to outside corridor to prevent air from blowing outwards • positive pressure relative to isolation room • PPE should be doffed & disinfected in anterooms

  43. 6. Temporary structures • Tents were used in Taiwan, Toronto & North Carolina to identify & isolate suspected SARS cases before they entered the hospitals • Veterans’ General Hospital, Taiwan: by using a tent, was the only E.D. to remain open • Included radiology & laboratory capabilities

  44. Level 2: Administrative Controls & Work Practices

  45. Written policies & procedures: 1. Infection Control Precautions • Health Care Infection Control Practices Advisory Committee (HICPAC) guidelines for SARS: • Standard precautions for all patients (whether deemed infectious or not) • Hand washing is still most important means of reducing transmission from person-to-person • Wearing gloves does not replace the need to wash hands. Why? micro-tears or contamination during glove removal • For suspect or probable SARS, also use all 3 transmission-based precautions: droplet, contact & airborne

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